CVE-2026-33173
Active Storage allows users to attach cloud and local files in Rails applications.
Does this matter?
Lower severity and a low EPSS score (0.39%). Track it; it rarely justifies an emergency change on its own.
Description
Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, `DirectUploadsController` accepts arbitrary metadata from the client and persists it on the blob. Because internal flags like `identified` and `analyzed` are stored in the same metadata hash, a direct-upload client can set these flags to skip MIME detection and analysis. This allows an attacker to upload arbitrary content while claiming a safe `content_type`, bypassing any validations that rely on Active Storage's automatic content type identification. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
- CVSS 4.0
- 5.3 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.39% probability · 33th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-925
- Affected
- rubyonrails/rails
- Source
- security-advisories@github.com
References
- https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53Patch
- https://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3ePatch
- https://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0Patch
- https://github.com/rails/rails/releases/tag/v7.2.3.1Release Notes
- https://github.com/rails/rails/releases/tag/v8.0.4.1Release Notes
- https://github.com/rails/rails/releases/tag/v8.1.2.1Release Notes
- https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cgVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.